In a bowl, mix 200g flour, the mustard powder, baking powder and half a teaspoon of salt. Rub in 100g butter, add four tablespoons of parsley and mix with about 75ml milk to form soft dough.

Cook the onions and garlic in a big pan with 75g butter for 10 minutes until soft, then scoop out, leaving the buttery juices behind. Add the lamb to the pan, cook for 20 minutes until the liquid has almost evaporated, add 25g flour and stir. Return the onion mix to the pan, add the rest of the milk and 250ml water, stir and season, then simmer, uncovered, until the lamb is tender.

Slice and boil the carrots, drain and add to the lamb with the remaining parsley. Spoon into a suitable ovenproof dish. Roll the pastry thinly, cut it into 2cm strips and weave a lattice over the top of the meat mix. Brush with milk and bake at 180C (160C fan-assisted)/350F/gas mark 4 for 30-40 minutes.